SR-71 Facts: 29 Details That Might Surprise You
The Last Of Its Kind
The SR-71 was built using a ‘slide rule’, and was the last major U.S. aircraft to do so. This mechanical numerical device is no larger than a ruler and contains all sorts of numbers that relate to each other based on the position of the middle ‘slide’. This tool has been used for complex multiplication for centuries, and is now replaced by high-tech calculators and computers. Later tests confirmed that the SR-71 would have been built the exact same way had the technology of today been around then.